POS1142 SPANISH NATIONAL REGISTRY OF BELIMUMAB IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS
Authors: M. Laino, M. Enguita, S. Castañeda, J. Loricera, C. Moriano, C. Lasa, V. Calvo-Río, J. Narváez, P. Navarro Palomo, I. Casafont-Solé, J. Font, A. Gallego, I. Carrión Barberà, P. Quiroga Colino, Á. García-Aparicio, J. M. Belzunegui Otano, M. López, J. R. De Dios Jiménez de Aberásturi, S. Hernández, S. Heredia, A. Fariña, F. J. Navarro Blasco, R. Ortega Castro, L. DEL Olmo Perez, E. Labrador-Sánchez, V. Pinillos, M. C. Ortega de la O, P. Castro, J. M. Blanco, M. Paulino Huertas, M. A. Matias de la Mano, C. Peralta-Ginés, S. Garcia-Cirera, J. Camins, A. Urruticoechea-Arana, M. Medina Malone, P. J. Cossio Jimenez, E. Perez-Pampín, B. Varas, C. Vázquez, N. Vegas-Revenga, O. Rusinovich, E. Giner, J. R. Lamúa-Riazuelo, V. Aldasoro
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Belimumab (BLM) is a monoclonal antibody that inhibits B-lymphocyte stimulating factor (BlyS) approved as a specific treatment for systemic lupus erythematosus (SLE) in 2011. We present the experience with BLM in a Spanish cohort with more than 460 patients. <h3>Objectives</h3> To describe demographic characteristics, efficacy and safety of BLM in patients with SLE in Spanish population since its approval. <h3>Methods</h3> Descriptive, retrospective, multicenter study in patients diagnosed with SLE according to EULAR/ACR 2019, SLICC and/or ACR 1997 diagnostic criteria. Data regarding SLE patients treated with BLM were collected from medical records (2011-2022). Demographic features, efficacy, laboratory variables, SLEDAI, renal involvement, steroid dose, administration routes and safety were assessed. To see whether a trend in BLM prescription had changed or not over time, two periods of time were analyzed: 2011-2016 (period1) and 2017-2022 (period2). <h3>Results</h3> Baseline characteristics of patients are summarized in Table 1. A total of 462 patients (36 hospitals) were included, 50.9% were on intravenous (IV), 34% on subcutaneous (SC) and 15.1% switched from IV to SC route. The median number of pre-BLM csDMARD use was 2.0 (2.0-3.0), being hydroxychloroquine (HCQ) the most frequently used (94.5%). Fifty-two patients were treated with IV cyclophosphamide with a median of 6 bolus received. At the time of BLM start, 443 patients were on prednisone with a median dose of 6.2 mg (5.0-10.0). Significant decreases in prednisone dose, SLEDAI and anti-DNA antibodies were observed from baseline until the last visit, whereas complement C3 and C4 values raised (Figure 1). A total of 118 patients (27.4%) had renal involvement with a median proteinuria of 1.0 g/day (0.5-2.4). Renal biopsy was done in 102 out of 118 patients, being class IV (33%), class III (21%) and class V (16%) the most frequently reported. After BLM, 73.3% of these patients improved (median proteinuria of 0.2 g/day (0.1-0.7). In period1, 100 patients started BLM compared to 362 in period2. The median time from SLE diagnosis to BLM begin was 7.1 (4.0-13.7) and 6.2 (2.1 -14.4) years in period1 and period2, respectively (p=0.454). We found a trend to use more csDMARD before BLM treatment in period1: 2.5 (2-3) vs. 2 (2-3) (p=0.088). A total of 143 (30.5%) patients discontinued treatment mostly due to inefficacy (55.9%) and infections (11.9%). In fact, 116 patients developed infections, mostly mild; 2 patients died, 16 had COVID-19 and 4 patients developed tumors requiring discontinuation of the drug. <h3>Conclusion</h3> In our cohort of SLE patients in a real-world setting, BLM has been effective, safe and seems to be a good choice to treat renal involvement. <h3>References</h3> [1]Navarra SV, Guzmán RM, Gallacher AE, et al. Lancet. 2011;377(9767):721-31. [2]Stohl W, Hiepe; rt al. Arthritis Rheum. 2012;64(7):2328-37. [3]Furie R, Rovin BH, Houssiau F, et al. N Engl J Med. 2020;383(12):1117-1128. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.